Variations in the cholesterol esterifying activity and cholesterol incorporation into the subcellular fractions of tissue obtained from swine fed various fats, cholesterol sources and vitamin D3 will be studied. Subcellular fractions of the intima and inner media of the thoracic, abdominal or whole coronary arteries, the heart, liver and adipose tissue of swine which had been fed a basal diet of soybean meal, and corn or the basal diet plus whole egg powder, hydrogenated fats or vitamin D3 will be incubated in vitro with 1-C14 labeled oleic, palmitic, linoleic or elaidic acid or 1,23H cholesterol. Esterification of the cholesterol in the microsomal and mitochondrial fractions will be determined. The effect of dietary fat and vitamin D upon sterol and fatty acid synthesis will be studied in vitro with the aid of 1-C14 labeled acetate or glucose as substrates. Pathological studies on the aorta tissue will also be carried out and the results correlated with the biochemical studies. All the experimental swine that will be used in this study will be obtained from a homogeneous swine population of known genetic background.